OLYMPIA, Wash. -- A brush fire sent campers running for cover as walls of flame raced through the Capitol Forest on Friday.

The so-called "Coyote Fire" began burning some time after 3 p.m. and spread quickly, prompting the evacuation of the campsite at Fall Creek.

By late Friday night, the blaze had already scorched 12 acres.

Three separate aircraft took turns ferrying water to drop over the burn zone as ground crews fought to douse the flames leaping off the floor of the 90,000-acre forest west of Olympia.

Officials with the state Department of Natural Resources say the fire started in a replanted area where timber had been harvested several years ago.

No buildings are at risk in the wooded area, but officials have issued a red-flag warning in Western Washington, citing timber-dry conditions. The brush at Capitol Forest is especially dry, officials said, and the blaze has not been contained.

The cause of the fire has not been determined, and the investigation is ongoing.